CVE-2021-3656HighConfirmedExploit available
AST
AST
Astra Linux Security Bulletins
Astra publishes per-release bulletins that map upstream CVEs to their own package repositories, with remediation timelines tied to the certification level (SE 1.7, CE 2.12, etc.). Indispensable for systems that require ФСТЭК/ФСБ clearance.
Region
RU
Updates
24 ч
License
Открытые данные
Vendor security bulletins for Astra Linux Special Edition and Common Edition — the primary certified Linux OS for Russian defense and critical infrastructure.
https://wiki.astralinux.ru/pages/viewpage.action?pageId=27362056 →Share link
Anyone with the link can open this vulnerability.
A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine …
CVSS
8.8
High
EPSS
0.01
p46
Published
2021-01-01
Updated
2021-01-01
Description
A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.
Tags · CWE
CWE-862
CWE-862ClassIncomplete
Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
https://cwe.mitre.org/data/definitions/862.html →Open in CWE collection →CAPEC-665
CAPEC-665DetailedStable
Exploitation of Thunderbolt Protection Flaws
https://capec.mitre.org/data/definitions/665.html →Open in CAPEC collection →
Affected products
KernelKernelKernelKernelKernelKernelKernelKernelKernelKernelKernel-rtKernel-rtKernel-rtLinuxLinuxLinuxLinuxLinuxLinuxLinux
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Timeline
2021-01-01
Published
2021-01-01
Updated
CVSS 3.1 breakdown
Attack Vector
AV: L
Local (L)
Attack Complexity
AC: L
Low (L)
Privileges Required
PR: L
Low (L)
User Interaction
UI: N
None (N)
Scope
S: C
Changed (C)
Confidentiality Impact
C: H
High (H)
Integrity Impact
I: H
High (H)
Availability Impact
A: H
High (H)
Exploit indicators
EPSS
0.007 · p46
Known exploited (KEV)
No
MITRE ATT&CK
Inferred via CAPEC
└ via CAPEC-665 · CWE-862
└ via CAPEC-665 · CWE-862
└ via CAPEC-665 · CWE-862
Known exploits — Сканер-ВС
CVE-2021-3656
github-poc · https://github.com/rami08448/CVE-2021-3656-Demo
Affected products
| Product | Vendor | Status |
|---|---|---|
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel | Tracked | |
| kernel-rt | Tracked | |
| kernel-rt | Tracked | |
| kernel-rt | Tracked | |
| linux | Tracked | |
| linux | Tracked | |
| linux | Tracked | |
| linux | Tracked | |
| linux | Tracked | |
| linux | Tracked | |
| linux | Tracked |
Showing first 20 of 332
Source databases
AST
AST
Astra Linux Security Bulletins
Astra publishes per-release bulletins that map upstream CVEs to their own package repositories, with remediation timelines tied to the certification level (SE 1.7, CE 2.12, etc.). Indispensable for systems that require ФСТЭК/ФСБ clearance.
Region
RU
Updates
24 ч
License
Открытые данные
Vendor security bulletins for Astra Linux Special Edition and Common Edition — the primary certified Linux OS for Russian defense and critical infrastructure.
https://wiki.astralinux.ru/pages/viewpage.action?pageId=27362056 →DEB
DEB
Debian Security Advisories (DSA)
DSAs are published by the Debian Security Team for issues affecting the stable distribution. The downstream tracker (security-tracker.debian.org) additionally maps every CVE to its package-level status across all supported suites.
Region
Intl.
Updates
1 ч
License
Public Domain
Advisories covering the Debian stable and oldstable releases. Ship notes include the exact .deb version that remediates each issue.
https://www.debian.org/security/ →CVE
CVE
National Vulnerability Database
NVD is the U.S. government repository of standards-based vulnerability management data, built on top of the MITRE CVE list. Every record includes CPE applicability statements, CVSS v2 and v3.x base scores, CWE mappings and cross-references to advisories.
Region
US
Updates
15 min
License
Public Domain
Comprehensive catalog of publicly disclosed vulnerabilities with CPE matches, CVSS scoring and reference URLs. De-facto standard for cross-vendor correlation.
https://nvd.nist.gov →RED
RED
Red Hat Security Advisories (RHSA)
Red Hat advisories are authoritative for RHEL-family systems: each record lists the exact package NEVRA fixed, the affected streams, and a Red Hat-assigned severity that may differ from NVD's. Many downstream projects (CentOS Stream, Rocky, Alma) follow these IDs.
Region
US
Updates
1 ч
License
CC BY-SA 4.0
Advisories for Red Hat Enterprise Linux, OpenShift, Ansible and other Red Hat products. Includes detailed backport tracking — critical for long-term-support distributions.
https://access.redhat.com/security/security-updates/ →UBU
UBU
Ubuntu Security Notices (USN)
USNs are authoritative for Ubuntu systems. The CVE Tracker links each vulnerability to its per-release status (needed, released, not-affected) and to the exact Launchpad bug where the fix is integrated.
Region
Intl.
Updates
1 ч
License
CC BY-SA 3.0
Security notices for Ubuntu LTS and interim releases, covering main, universe and (via Pro) ESM-extended packages.
https://ubuntu.com/security/notices →Related vulnerabilities